Production of cover fabrics for V belts which function as wear indicators due to different layer characteristics

Abstract

A cover fabric for a V belt having increased flex and wear-life, and a method of making the cover fabric. A fabric is bias cut into a continuous strip of fabric. The individual fibers in the continuous strip are impregnated with an elastomeric polymeric material effective to increase the flex and wear-life of the fabric when used as a cover fabric for V belts. This impregnation is accomplished by immersing the strip in a fluid mix having a viscosity of about 2000 cps or less, the mix including a fluid carrier, an elastomeric polymer (e.g. a polychloroprene compound) and a dark pigment. A coating of an elastomeric polymer (e.g. another polychloroprene compound) is applied to the strip, the strip is stretched in its width direction to increase the angular relation of the threads of the fabric relative to its longitudinal axis, and the thus coated strip is dried. The continuous strip is ultimately slit longitudinally of itself into a plurality of tapes, and the tapes are used to cover a V belt.

What is claimed is: 
     
       1. An industrial cover fabric for power transmission belts or the like, consisting of a strip of bias cut fabric woven from blended fiber yarns, the individual fibers of said yarns being encapsulated in a dried pigmented elastomeric polymer, and said yarns and encapsulated fibers being over coated with a dried elastomeric polymer, the angular orientation between the warp and weft yarns of said woven fabric being increased to an angle greater than 90° and being held in that position by the dried elastomeric coating, said industrial cover fabric having greatly increased wear life by virtue of said individual fiber encapsulation, the pigment in said pigmented elastomeric polymer being adapted to abrade off with said polymer to reveal unpigmented portions of said fibers when said fabric has outlived its usefulness. 
     
     
       2. The product of claim 1 wherein the elastomeric polymer is a polychloroprene, and the pigment is a conductive carbon black. 
     
     
       3. A bias cut woven fabric cover for a V belt or the like, the fabric cover being produced from a continuous fabric strip by impregnating the individual fibers in the strip with a fluid mix including an elastomeric polymer, a dark pigment and a fluid, and having a viscosity of about 2000 cps or less; applying an elastomeric coating to the strip; and drying the strip. 
     
     
       4. A bias cut woven fabric cover for a V belt or the like, the fabric cover being produced from a continuous fabric strip by impregnating the individual fibers in the strip with an elastomeric polymeric material effective to increase the wearlife of the fabric when covering a V belt or the like, applying an elastomeric coating to the strip, and drying the thus coated strip. 
     
     
       5. A method of making a cover fabric for V belts or the like, comprising the steps of (a) cutting a fabric into a continuous strip of fabric;   (b) impregnating the individual fibers in the continuous strip of fabric with an elastomeric polymeric material effective to increase the wearlife of the fabric when used as a cover fabric for V belts or the like;   (c) applying an elastomeric coating to the strip;   (d) stretching the strip in its width direction to increase the angular relation of the threads of the fabric relative to its longitudinal axis; and   (e) drying the thus coated strip.   
     
     
       6. A method as recited in claim 5 wherein step (b) is practiced by immersing the strip in a low viscosity fluid mix of polymeric material, and removing excess mix, prior to practicing step (c). 
     
     
       7. A method as recited in claim 6 wherein excess mix is removed utilizing a pair of textile pad rolls through which the fabric passes after immersion in a dip tank. 
     
     
       8. A method as recited in claim 5 wherein steps (c) and (d) are practiced directly after step (b), with no drying in between. 
     
     
       9. A method as recited in claim 5 comprising the further step of, simultaneously with step (b), improving the cosmetic effect of the fabric by coloring the fabric fibers with a dark pigment. 
     
     
       10. A method as recited in claims 5, 6, 8, or 9 wherein step (b) is accomplished by impregnating the fabric with a fluid mix having a viscosity of about 2000 cps or less. 
     
     
       11. A method as recited in claims 5, 6, 8, or 9 wherein step (b) is accomplished by impregnating the fabric with a fluid mix comprising an elastomeric polymer and a dark pigment. 
     
     
       12. A method as recited in claims 5, 6, 8, or 9 wherein step (b) is accomplished by impregnating the fabric with a fluid mix comprising a major portion of an elastomeric polymer and a minor portion of dark pigment, and the fluid mix having a viscosity of about 2000 cps or less. 
     
     
       13. A method as recited in claims 5 or 9 wherein step (b) is accomplished by impregnating the fabric with a solvent mix comprising a major portion of an elastomeric polychloroprene compound and a minor portion of dark pigment, and the solvent mix having a solids range of about 2-20%, and a viscosity of about 1500±250 cps. 
     
     
       14. A method as recited in claims 5 or 9 comprising the further steps of: slitting the continuous strip longitudinally of itself into a plurality of tapes for covering a V belt or the like. 
     
     
       15. A method as recited in claim 5 wherein the fabric step (a) is accomplished by slitting the fabric to obtain an angle of between 15° and 60°. 
     
     
       16. A method of treating a bias cut woven fabric continuous strip so that it is suitable for use as a cover fabric for V belts or the like, comprising the steps of (a) impregnating the individual fibers in the strip with a fluid mix including an elastomeric polymer, a dark pigment, and a fluid carrier, said fluid mix having a viscosity of about 2000 cps or less;   (b) applying an elastomeric coating to the strip; and   (c) drying the strip.   
     
     
       17. A method as recited in claim 16 wherein a conductive black is employed as the dark pigment. 
     
     
       18. A method as recited in claim 16 wherein the fluid carrier is a solvent, and the fluid mix is a solvent mix. 
     
     
       19. A method as recited in claim 16 wherein the fluid carrier is water, and the fluid mix is an aqueous mix.